earthquake- the movement deep underground that occurs when stress releases stress- the energy released during an earthquake shearing- the stress force that makes two rocks go in different directions tension- the stress force that stretches rock until it breaks or changes compression- the stress force that squeezes rock deformation- the changes caused by the forces of stress fault- a crack in the earth's crust that forms after an earthquake strike-slipfaults- caused by shearing, rocks move past each other but with barely any up-and-down movement normalfaults- caused by tension, creates a slanted fault leaving one rock above the other hanging wall- the hanging wall lies below the footwall in a normal fault but is the opposite in a reverse fault footwall- the footwall is above the hanging wal in a normal fault, but is the opposite in a reverse fault reversefaults- caused by compression, also creates a slanted fault leaving the previous rock below the other rock fault-block-mountain- a mountain formed by two faults that carry a rock mass folds- when compression occurs and either rock doesn't give in, the rock folds anticline- caused by folding, uplifts rock creating a hump syncline- also caused by folding, the space between the hump (anticline) plateau- caused by compression, a large mass of rock above the sea
Outline
Stress in the crust
Earthquake
caused by stress
three types of stress tension, compression, shearing
all these forces cause deformation
mountains, faults, footwalls, hanging walls
Types of Stress
Tension
stretches rock to become thinner in the middle or until it breaks
causes normal fault
Shearing
causes rocks to break and slip past each other
causes strike-slip fault
Compression
pushes rock together
can make rock break or fold
can make a reverse fault
Kinds of Faults
Strike-Slip Faults
two rocks slip past each other from shearing
not much up or down movement
if between plates, fault called transform boundary
Normal Faults
Tension creates fault at an angle
one rock lies bellow the other
in normal faults only, a footwall is the rock that is above the hanging wall
When tension occurs, hanging wall goes downward
Reverse Faults
opposite of normal fault, but caused by compression
foot wall is below hanging wall in a reverse fault
Friction Along Faults
Friction is the force that opposes the motion of one surface as it moves across another surface.
lower the friction, the less rock sticks, higher the friction is, the more rocks lock
friction high in some places, when stress releases them in those places, an earthquake is created
like the San Andreas fault
Mountain Building
rocks can use forces of stress to change earths surface.
Mountains Formed by Faulting
when normal faults uplift a block of rock, a fault block mountain forms
two normal faults
When the middle block slips down a valley formes like the Sierra Nevada, Great Basin, and Mojave desert
when two hanging walls slip down, middle block goes up
Mountains formed by folds
sometimes crust folds when pushed together by other crust by compression
Himalayas and the Alps were caused by folding
Some folding collisions form earth quakes because folding rocks can fracture and produce faults \
*
Anticlines and Syniclines
caused by folding
anticlines= upward bump of a fold
synicline= downward bump of a fold.
in black hills south of Dakota and Illinois Basin this occured
Plateaus
plateaus are large areas where FLAT land above sea are
different flat layers, some are wider than it is tall like the Colorado Plateau.
Table of Contents
Earth's Crust in Motion
Vocabulary
earthquake- the movement deep underground that occurs when stress releases
stress- the energy released during an earthquake
shearing- the stress force that makes two rocks go in different directions
tension- the stress force that stretches rock until it breaks or changes
compression- the stress force that squeezes rock
deformation- the changes caused by the forces of stress
fault- a crack in the earth's crust that forms after an earthquake
strike-slip faults- caused by shearing, rocks move past each other but with barely any up-and-down movement
normal faults- caused by tension, creates a slanted fault leaving one rock above the other
hanging wall- the hanging wall lies below the footwall in a normal fault but is the opposite in a reverse fault
footwall- the footwall is above the hanging wal in a normal fault, but is the opposite in a reverse fault
reverse faults- caused by compression, also creates a slanted fault leaving the previous rock below the other rock
fault-block-mountain- a mountain formed by two faults that carry a rock mass
folds- when compression occurs and either rock doesn't give in, the rock folds
anticline- caused by folding, uplifts rock creating a hump
syncline- also caused by folding, the space between the hump (anticline)
plateau- caused by compression, a large mass of rock above the sea
Outline
Stress in the crust
Types of Stress
Kinds of Faults
Friction Along Faults
Mountain Building
- rocks can use forces of stress to change earths surface.
- Mountains Formed by Faulting
- when normal faults uplift a block of rock, a fault block mountain forms
- two normal faults
When the middle block slips down a valley formes like the Sierra Nevada, Great Basin, and Mojave desert
- when two hanging walls slip down, middle block goes up
- Mountains formed by folds
- sometimes crust folds when pushed together by other crust by compression
- Himalayas and the Alps were caused by folding
- Some folding collisions form earth quakes because folding rocks can fracture and produce faults \
*Anticlines and Syniclines
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